Air-compressing internal combustion engine with a precombustion chamber

ABSTRACT

An air-compressing internal combustion engine which includes a cylinder block, a plurality of cylinders in the cylinder block, a piston reciprocably mounted in the respective cylinders, and a cylinder head disposed on the cylinder block. A precombustion chamber is arranged in the cylinder head and associated with the respective cylinders and a number of approximately radially extending burner holes are provided around a periphery of an end of the precombustion chamber. A depression is arranged in the head of each of the pistons and stellate depressions emanate from the depression in the cylinder head. Each of the stellate depressions ascend continuously in a radially outward direction and a further substantially axially extending burner hole is provided at the end of the precombustion chamber.

The present invention relates to an internal combustion engine and, moreparticularly, to an air-compressing fuel-injected internal combustionengine which includes a precombustion chamber arranged in a cylinderhead with an end of the precombustion chamber, provided withapproximately radially extending burner holes, extending, at a top deadcenter position of a piston of the engine into a depression arranged inthe piston head, with stellate depressions emanating from the depressionarranged in the piston head, which depressions correspond in number anddirection to the radially extending burner holes.

In German Pat. No. 891,767, an internal combustion engine is proposedwherein stellate depressions are provided in the piston head, whichdepressions are adapted, in their cross sectional shape, to the form ofthe fuel-air mixture jet exiting from the precombustion chamber so thata respectively metered amount of air can be admixed to each fuel-airmixture jet, in such a distribution that each cross sectional portion ofthe fuel-air mixture jet has available an appropriate amount of airprovided by the corresponding cross sectional portion of the associateddepression.

A disadvantage of this proposed construction resides in the fact that,the air accumulation for each fuel-air mixture jet is provided remotefrom the precombustion chamber and only a small amount of air is presentin the direct vicinity of the precombustion chamber. Although suchproposed arrangement leads to an advantageous fuel consumption and to anincrease in power, additional disadvantages arise such as, for example,poor starting characteristics, low compression ratio, explosion-likecombustions, and others.

The aim underlying the present invention essentially resides inproviding an air-compressiong fuel-injected combustion engine whichexhibits higher compression and which enables an improved combustionprocess so that the power output of the engine is increased, the fuelconsumption is lowered, and the emission of deleterious substances issubstantially reduced.

In accordance with advantageous features of the present invention, thestellate depressions which emanate from the depression in the pistonhead are disposed so as to ascend continuously radially outwardly towardthe piston head with a further, substantially axially extending burnerhole being provided at the end of the precombustion chamber.

By virtue of the above noted features of the present invention, anaccumulation of combustion air is produced in a zone of the combustionchamber and, although there is an accumulation of the combustion air,this accumulation is continuously reduced by the continuously ascendingstellate depressions so that an entire free volume is kept small and ahigher compression is made possible.

Moreover, by virtue of the present invention, an air volume present in azone of the precombustion chamber is displaced by the burner holeoriented toward the piston head primarily in a direction toward thestellate depressions and thus is conducted into the same direction asthe fuel-air mixture jets so that an intensive intermixing as well as aconstant replenishment of the oxygen takes place from the zone of thedepression. This intermixing progresses radially over an entire surfaceof the piston head so that an ideal combustion is attained at a highercompression.

Moreover, by virtue of the present invention a blackening rate in theexhaust gas is lower than usual and the proportion of half-combustedhydrocarbons is about 40% below the limit attained in a conventionalinternal combustion engine with a vortex chamber.

Accordingly, it is an object of the present invention to provide anair-compressing fuel-injected internal combustion engine which avoids,by simple means, shortcomings and disadvantages encountered in the priorart.

Another object of the present invention resides in providing anair-compressing fuel-injected internal combustion engine in which thestarting characteristics are improved.

Yet another object of the present invention resides in providing anair-compressing fuel-injected internal combustion engine which has animproved combustion so that the mean pressure and the power of theinternal combustion engine are increased.

A further object of the present invention resides in providing anair-compressing fuel-injected internal combustion engine which operateswith a substantially lower fuel consumption.

A still further object of the present invention resides in providing anair-compressing internal combustion engine which substantially reducesthe emission of hydrocarbons and other deleterious substances in theexhaust gas.

Another object of the present invention resides in providing anair-compressing fuel-injected internal combustion engine which functionsrealiably in all operating phases of the engine.

These and other objects, features, and advantages of the presentinvention will become more apparent from the following description whentaken in connection with the accompanying drawings which show, for thepurposes of illustration only, one embodiment in accordance with thepresent invention, and wherein:

FIG. 1 is a partiall cross sectional view of an internal combustionengine in accordance with the present invention;

FIG. 2 is a top view of the piston of the internal combustion engine ofFIG. 1.

Referring now to the drawings wherein like reference numerals are usedin both views to designate like parts and, more particularly, to FIGS. 1and 2, according to these figures, an internal combustion engine isprovided which includes a cylinder block 1 having a cylinder head 2wherein valves 3 in a precombustion chamber 4 are arranged. Theprecombustion chamber 4 is provided with a plurality of burner holes 5arranged about a periphery thereof, with the burner holes 5 extending ina radial direction. The burner holes 5 lie substantially in a plane of apiston head 7 in a top dead center position of the piston 6. A furtherburner hole 8 is provided at the end of the precombustion chamber 4 withthe burner hole 8 being arranged so as to extend substantially axiallytoward the piston head 7 of the piston 6. A depression generallydesignated by the reference numeral 9 is provided in the piston head 7and, at top dead center position of the piston 6, the end of theprecombustion chamber 4 enters the depression 9 with a gap remainingbetween the end of the precombustion chamber 4 and the surface of thedepression 9.

Stellate depressions 10 emanate from the depression 9 in the piston head7, with the stellate depressions 10 being respectively associated withthe burner holes 5. The depressions 10 each ascend continuously radiallyoutwardly toward the piston head. In this connection, the respectivestellate depressions 10 are configured so that they are rounded in crosssection and, preferably, in a lenticular form, and also so that theyhave a depth which is lower than their width.

Due to the provision of a depression in each of the piston heads 7 ofthe respective piston 6, an accumulation of a free volume is produced ina zone of the end of the precombustion chamber 4 in a top dead centerposition of the piston 6. However, the proportion of combustion aircollected in the depression 9 is urged into the stellate depressions 10by the fuel-air mixture jets exiting from the burner hole 8. In thestellate depression 10, an intensive intermixing occurs with aproportion of the combustion air present therein and with the fuel-airmixture jets exiting in the same direction from the burner holes 5.

While I have shown and described only one embodiment in accordance withthe present invention, it is understood that the same is not limitedthereto but is susceptible of numerous changes and modifications asknown to one having ordinary skill in the art and I therefore do notwish to be limited to the details shown and described herein, but intendto cover all such modifications as are encompassed by the scope of theappended claims.

I claim:
 1. An air-compressing fuel-injected internal combustion enginecomprising a cylinder block, a plurality of cylinders in the cylinderblock, a piston reciprocably mounted in the respective cylinders, acylinder head disposed on said cylinder block, a precombustion chamberarranged in the cylinder head and associated with the respectivecylinders, a plurality of approximately radially extending burner holesprovided around a periphery of an end of the precombustion chamber,adepression arranged in a head of each of the pistons, the end of theprecombustion chamber extending into the depression when an associatedpiston is in a top dead center position thereof, and stellatedepressions emanating from the depression in the cylinder head andcorresponding in number and direction to the plurality of radiallyextending burner holes and being adapted in their cross-sectional shapeto the form of the fuel-air mixture jets exiting from said burner holes,each of the stellate depressions ascending continuously in a radiallyoutward direction for reducing the free volume between the piston andthe cylinder head in the top dead center position, and a furthersubstantially axially extending burner hole being provided at the end ofthe precombustion chamber and oriented into the depression of the pistonhead, characterized in that the stellate depressions each have alenticular configuration.
 2. An air-compressing fuel-injected internalcombustion engine comprising a cylinder block, a plurality of cylindersin the cylinder block, a piston reciprocably mounted in the respectivecylinders, a cylinder head disposed on said cylinder block, aprecombustion chamber arranged in the cylinder head and associated withthe respective cylinders, a plurality of approximately radiallyextending burner holes provided around a periphery of an end of theprecombustion chamber,a depression arranged in a head of each of thepistons, the end of the precombustion chamber extending into thedepression when an associated piston is in a top dead center positionthereof, and stellate depressions emanating linearly from the depressionin the cylinder head and corresponding in number and direction to theplurality of radially extending burner holes and being adapted in theircross-sectional shape to the form of the fuel-air mixture jets exitingfrom said burner holes, each of the stellate depressions ascendingcontinuously in a radially outward direction for reducing the freevolume between the piston and the cylinder head in the top dead centerposition, and a further substantially axially extending burner holebeing provided at the end of the precombustion chamber and oriented intothe depression of the piston head, the plurality of radially extendingburner holes lie substantially in a plane of the piston head when thepiston is in a top dead center position, and characterized in that thestellate depressions each have a lenticular configuration.